Cloning and expression analysis of zinc-finger transcription factor MeDi19-1 gene in cassava

【Objective】In this study，a zinc finger transcription factor MeDi19-1 was cloned from cassava. Its coding protein characteristics，subcellular localization，transcriptional activation activity and expression levels in different tissues of cassava were analyzed. This research laid a foundation for further exploration of the function and mechanism of MeDi19-1 in cassava.【Method】The coding region sequence（CDS）of MeDi19-1 gene was amplified from cDNA of cassava KU50.The bioinformatics analysis predicted the physicochemical properties.The pNC-Green-SubC-MeDi19-1 fusion expression vector was also constructed. By Agrobacterium-mediated transfection of tobacco epidermal cells，and the fluorescence signal was observed to determine the protein subcellular localization.The yeast system was used to determine its transcriptional activation activity，and its tissue expression properties were analyzed based on transcriptomic data from different tissues in cassava.【Result】The CDS of MeDi19-1 gene（OL620080）was 618 bp in length and encoded 205 amino acids with molecular weight of 22416.79 Da and theoretical isoelectric point（pI）of 6.10. MeDi19-1 protein belonged to an unstable hydrophobin and contained the zinc finger domainzf-Di19 which was typical in Di19 protein family. The se-condary structure of the MeDi19-1 protein contained irregularly coils（53.66%），α -helix（40.49%），extended chain （4.39%）and β-turn（1.46%）. The amino acid sequence of MeDi19-1 protein had the highest similarity（83.50%）to the amino acid sequence of Hevea brasiliensis Di19-6 protein（XP_021655585.1）. The promoter of MeDi19-1 contained the cis-acting element involved in the response to abscisic acid（ABA），gibberellin，jasmonic acid，stress response element and light response element. MeDi19-1 protein was located in nucleus and cytomembrane. MeDi19-1 protein had transcriptional activation activity，and its active region was at the C-terminus. MeDi19-1 showed high expression levels in leaf，midveins and storage root.【Conclusion】The MeDi19-1 gene is a member of the Di19 gene family，has tissue expression specificity and may play a regulatory role in leaves，mid-veins and storage roots，and its encoded protein is involved in the regulation of multiple physiological activities as transcription factors in cassava tissues.